Different LED Colors and Pre-Drying Treatments Enhance Isoflavonoid Production and Estrogenic Activity in Pueraria candollei Callus Cultures.

Abstract

Callus cultures of Pueraria candollei are effective phytoestrogen sources and are a feasible commercial alternative to agricultural farming and traditional cultivation due to their rapid growth and sufficient production of bioactive compounds. How different light wavelengths impact secondary metabolite accumulation in callus cultures of P. candollei remains unclear. In this study, we focused on enhancing phytoestrogen levels in P. candollei callus extracts treated under different light conditions and pre-drying methods. Metabolite production, and estrogenic and anti-inflammatory activity of callus extracts were investigated using MCF-7 and RAW 264.7 cells, respectively. Callus cultured under white LED produced the highest growth index on Day 28 and stimulated significant upregulation of HID, CYP81E, and PT-1 by 1.6-, 4.8-, and 56-fold, respectively. Callus treated with red LED increased daidzin, genistin, and deoxymiroestrol levels (0.613 ± 0.042 mg g^-1, 0.549 ± 0.033 mg g^-1, and 1.46 ± 0.24 μg g^-1 dry weight, respectively). The total isoflavonoid content in the callus extract increased by 3- and 2-fold under red and white LED lights, respectively. The extract of callus-treated white LED at Day 28 significantly suppressed nitric oxide production from 100% to 54.8% ± 2.8%. The strongest estrogenic activity was obtained in callus extract grown under red LED with a pre-drying step, which was attributed to higher levels of deoxymiroestrol. The red and white LED light stimulated the formation of phytoestrogens in callus cultures of P. candollei. The pre-drying treatment enhanced aglycone secondary metabolites and pharmacological activity of callus. Our findings indicate that the therapeutic potential of P. candollei can be enhanced by facilitating controlled and efficient production of its bioactive compounds.